diff options
Diffstat (limited to 'arch/x86/include/asm/uaccess.h')
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 111 |
1 files changed, 17 insertions, 94 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index a0ae610b9280..faf3687f1035 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -11,6 +11,7 @@ #include <asm/asm.h> #include <asm/page.h> #include <asm/smap.h> +#include <asm/extable.h> #define VERIFY_READ 0 #define VERIFY_WRITE 1 @@ -91,37 +92,6 @@ static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, un likely(!__range_not_ok(addr, size, user_addr_max())) /* - * The exception table consists of triples of addresses relative to the - * exception table entry itself. The first address is of an instruction - * that is allowed to fault, the second is the target at which the program - * should continue. The third is a handler function to deal with the fault - * caused by the instruction in the first field. - * - * All the routines below use bits of fixup code that are out of line - * with the main instruction path. This means when everything is well, - * we don't even have to jump over them. Further, they do not intrude - * on our cache or tlb entries. - */ - -struct exception_table_entry { - int insn, fixup, handler; -}; - -#define ARCH_HAS_RELATIVE_EXTABLE - -#define swap_ex_entry_fixup(a, b, tmp, delta) \ - do { \ - (a)->fixup = (b)->fixup + (delta); \ - (b)->fixup = (tmp).fixup - (delta); \ - (a)->handler = (b)->handler + (delta); \ - (b)->handler = (tmp).handler - (delta); \ - } while (0) - -extern int fixup_exception(struct pt_regs *regs, int trapnr); -extern bool ex_has_fault_handler(unsigned long ip); -extern void early_fixup_exception(struct pt_regs *regs, int trapnr); - -/* * These are the main single-value transfer routines. They automatically * use the right size if we just have the right pointer type. * @@ -433,7 +403,11 @@ do { \ #define __get_user_asm_ex(x, addr, itype, rtype, ltype) \ asm volatile("1: mov"itype" %1,%"rtype"0\n" \ "2:\n" \ - _ASM_EXTABLE_EX(1b, 2b) \ + ".section .fixup,\"ax\"\n" \ + "3:xor"itype" %"rtype"0,%"rtype"0\n" \ + " jmp 2b\n" \ + ".previous\n" \ + _ASM_EXTABLE_EX(1b, 3b) \ : ltype(x) : "m" (__m(addr))) #define __put_user_nocheck(x, ptr, size) \ @@ -697,44 +671,15 @@ unsigned long __must_check _copy_from_user(void *to, const void __user *from, unsigned long __must_check _copy_to_user(void __user *to, const void *from, unsigned n); -#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS -# define copy_user_diag __compiletime_error -#else -# define copy_user_diag __compiletime_warning -#endif - -extern void copy_user_diag("copy_from_user() buffer size is too small") -copy_from_user_overflow(void); -extern void copy_user_diag("copy_to_user() buffer size is too small") -copy_to_user_overflow(void) __asm__("copy_from_user_overflow"); +extern void __compiletime_error("usercopy buffer size is too small") +__bad_copy_user(void); -#undef copy_user_diag - -#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS - -extern void -__compiletime_warning("copy_from_user() buffer size is not provably correct") -__copy_from_user_overflow(void) __asm__("copy_from_user_overflow"); -#define __copy_from_user_overflow(size, count) __copy_from_user_overflow() - -extern void -__compiletime_warning("copy_to_user() buffer size is not provably correct") -__copy_to_user_overflow(void) __asm__("copy_from_user_overflow"); -#define __copy_to_user_overflow(size, count) __copy_to_user_overflow() - -#else - -static inline void -__copy_from_user_overflow(int size, unsigned long count) +static inline void copy_user_overflow(int size, unsigned long count) { WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count); } -#define __copy_to_user_overflow __copy_from_user_overflow - -#endif - -static inline unsigned long __must_check +static __always_inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n) { int sz = __compiletime_object_size(to); @@ -743,36 +688,18 @@ copy_from_user(void *to, const void __user *from, unsigned long n) kasan_check_write(to, n); - /* - * While we would like to have the compiler do the checking for us - * even in the non-constant size case, any false positives there are - * a problem (especially when DEBUG_STRICT_USER_COPY_CHECKS, but even - * without - the [hopefully] dangerous looking nature of the warning - * would make people go look at the respecitive call sites over and - * over again just to find that there's no problem). - * - * And there are cases where it's just not realistic for the compiler - * to prove the count to be in range. For example when multiple call - * sites of a helper function - perhaps in different source files - - * all doing proper range checking, yet the helper function not doing - * so again. - * - * Therefore limit the compile time checking to the constant size - * case, and do only runtime checking for non-constant sizes. - */ - if (likely(sz < 0 || sz >= n)) { check_object_size(to, n, false); n = _copy_from_user(to, from, n); - } else if (__builtin_constant_p(n)) - copy_from_user_overflow(); + } else if (!__builtin_constant_p(n)) + copy_user_overflow(sz, n); else - __copy_from_user_overflow(sz, n); + __bad_copy_user(); return n; } -static inline unsigned long __must_check +static __always_inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n) { int sz = __compiletime_object_size(from); @@ -781,21 +708,17 @@ copy_to_user(void __user *to, const void *from, unsigned long n) might_fault(); - /* See the comment in copy_from_user() above. */ if (likely(sz < 0 || sz >= n)) { check_object_size(from, n, true); n = _copy_to_user(to, from, n); - } else if (__builtin_constant_p(n)) - copy_to_user_overflow(); + } else if (!__builtin_constant_p(n)) + copy_user_overflow(sz, n); else - __copy_to_user_overflow(sz, n); + __bad_copy_user(); return n; } -#undef __copy_from_user_overflow -#undef __copy_to_user_overflow - /* * We rely on the nested NMI work to allow atomic faults from the NMI path; the * nested NMI paths are careful to preserve CR2. |